Details: Blood Golems are linked to the Necromancer who casts them. As the Blood Golem damages the target it leeches life, and shares this with the Necromancer. Before v1.13, the Necromancer would also lose life as the golem took damage, but this is no longer the case.

The Golem gains 70% of the health it steals while the player gains 30%. If the current life + stolen life > maximum life of the Blood Golem, the Hit Point overflow goes to the Necromancer. If the current life + stolen life > maximum life of the Necromancer, the Hit Point overflow returns to the Golem up to the maximum life for each target.